Can you use more enter? I don't understand 3. Please also provide, how far could you get with the solutions. Use $ for mathematical formulas, \subseteq for subset and \to for arrow, and \{ and \} for the set parenthesis.
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BerciApr 2 '13 at 10:47

Edited. I'm only guessing at the symbol between A and Y, since it came across as a blank square.
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Thomas AndrewsApr 2 '13 at 10:52

5

It might help to have a more specific title.
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Hui YuApr 2 '13 at 14:44